S = input()
c_w_w =[]
for x in range(len(S)):
    if S[x] == "c":
        for y in range(x+1,len(S)):
            if S[y] == "w":
                for z in range(y+1,len(S)):
                    if S[z] == "w":
                        c_w_w.append(z - x + 1)
if len(c_w_w) != 0:
    print(min(c_w_w))
else:
    print(-1)